What does it mean to have a calcified granulomas lung disease? Is this something serious? Is it treatable?

No. Calcified granulomas are a sign of prior TB or a fungal infection called histoplasmosis. They are a common finding and are not serious.
No. It is evidence of a prior infection. In other words, it's a scar. It is not serious and does not require treatment. When it is not calcified, we follow them with repeat ct scans over 2 years.